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Protective Effect of Melatonin Against Chromium-Induced Hepatotoxic and Genotoxic Effect in Albino Rats

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Protective Effect of Melatonin Against Chromium-Induced Hepatotoxic and Genotoxic Effect in Albino Rats Global Veterinaria 16 (4): 323-329, 2016 ISSN 1992-6197 © IDOSI Publications, 2016 DOI: 10.5829/idosi.gv.2016.16.04.10332 Protective Effect of Melatonin Against Chromium-Induced Hepatotoxic and Genotoxic Effect in Albino Rats Emad A. Hashish and Shimaa A. Elgaml Department of Clinical Pathology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Sharkyia, Egypt Abstract: Chromium is a widespread environmental waste. It is an industrial contaminant with teratogenic, mutagenic and carcinogenic effects on animals and human. This study was carried out to evaluate the potential protective effect of melatonin on the hepatotoxicity and genotoxicity generated by potassium dichromate (K2 Cr 27 O ) in albino rats. Rats were divided into four groups; control, melatonin (10 mg/kg b.wt.), melatonin pretreated with single S/C injection of K2 Cr 27 O (15 mg/kg b.wt.) and potassium dichromate treated group. Rats were sacrificed 24 h after K2 Cr 27 O treatment. K2 Cr 27 O treated rats showed significant (P<0.05) increase in the hepatic marker enzymes activity (aspartate aminotransferase-AST and alanine aminotransferase-ALT) and serum bilirubin (total and direct) was detected. Significant (P<0.05) decrease in the serum total protein and albumin was observed after K2 Cr 27 O treatment. Meanwhile, serum globulin, A/G ratio and indirect bilirubin showed no significant change. Hepatic DNA damage was observed using comet assay. The histological alterations confirmed the previous results. Melatonin pretreated rats showed an amelioration of the adverse effects of K2 Cr 27 O toxicity. An improvement in the serum hepatic enzymes (AST and ALT), proteinogram (total protein and albumin) and bilirubin (total and direct) was observed. Melatonin pre-treatment showed significant improvement in the hepatic DNA and the histopathological picture. It could be concluded that potassium dichromate is hepatotoxic and genotoxic. Melatonin has a potential protective effect to reverse the DNA damage and has the ability to improve the hepatic function associated with K2 Cr 27 O intoxication. Key words: Chromium Hepatotoxicity Genotoxicity Melatonin INTRODUCTION activities of enzymes involved in the antioxidative defense [3]. It protects the liver in several models of liver injury via Chromium is a transition metal which can be found in inhibiting the oxidative and the nitrosative damage [4]. many compounds of Earth's crust. It is ranked the 21st in Its protection against the oxidative damage is enhanced elemental abundance. Chromium comes from several by its amphiphilic nature. The melatonin molecule is anthropogenic sources such as chemical, metallurgical readily access to all cell compartments including and refractory industry [1]. It is responsible for various the nucleus [5]. Melatonin stimulates the immune health hazards including cancers, dermatitis, damage to response and exhibits immunomodulatory effects [6]. the liver and kidney, infertility in both males and females, The immunomodulatory properties include the inhibition defects in embryo and developmental problems in young of the expression of cyclooxygenase 2 (COX-2) and children [2]. inducible nitric oxide synthase (iNOS) to exert marked Melatonin (N-acetyl-5-methoxytryptamine) is the anti-inflammatory effect [7]. It also mitigates the oxidative main product of the pineal gland in both stress and the vital organ damage induced by heavy animals and human. It plays a major role in the metals and snake venom toxicity [8, 9]. neuroimmuno-endocrine system. Melatonin participates Intensive research over the last two decades has in many vital physiological functions such as reported the beneficial protective effect of melatonin in a anti-inflammatory and a broad spectrum antioxidant. multitude of pathological processes. It is considered as an It decreases the level of free radical by stimulating the immunostimulant for both humeral and cellular immunity Corresponding Author: Shimaa A Elgaml, Clinical Pathology Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt, 44511. Cell: +201009168681, Fax: +20552283683. E-mail: [email protected]. 323 Global Veterinaria, 16 (4): 223-329, 2016 [10]. No previous studies reported the protective effect of flow smoothly into the tubes, left at room temperature for melatonin against chromium induced hepatoxicity. 2 hours to clot then centrifuged at 3000 rpm for 15 min. Therefore, in the present investigation, an attempt was The clear supernatant serum was collected using sterile made to evaluate the protective effect of melatonin on Pasteur pipettes. Serum was transferred to sterile, potassium dichromate mediated hepatotoxicity in order to dry labeled eppendorf tubes for chemical analysis. study the role of melatonin in the amelioration of the Liver from all groups was removed, washed with saline chromium intoxication. and cut into two parts, one part was preserved at -20°C for comet assay and the other part was preserved in MATERIALS AND METHODS 10% neutral-buffered formalin for the histological investigation. Chemicals: Melatonin was obtained from Sigma-Aldrich (product number M5250). Melatonin was administered as Biochemical Analysis: All biochemical analysis was single intraperitoneal injection 10 mg/kg b.wt., daily for 10 calorimetrically measured using commercial kits provided successive days [11] before induction of acute toxicity. by bioMérieux, France. The analysis was done using a Potassium dichromate (K2 Cr 27 O ) was obtained from spectrophotometer (5010 v5C, RIELE GmbH, Berlin, Sigma-Aldrich (product number 207802). It was used to Germany). induce acute toxicity. Rats were given a single subcutaneous (S/C) injection of K2 Cr 27 O at a dose of Serum Enzymes: Serum aspartate aminotransferase (AST) 15 mg/kg b.wt. [12]. and serum alanine aminotransferase (ALT) activity were determined [13]. Experimental Animals: Thirty two female albino rats weighing 150-200 g were obtained from the Laboratory Serum Proteins: Serum total protein was colometrically Animal House, Helwan, Egypt. Throughout the measured [14]. Serum albumin was colometrically experiment, all animals were housed in clean hygienic measured [15]. Serum globulin level was determined by metal cages inside environmentally controlled room and subtracting the albumin from the total proteins. kept under a uniform laboratory condition. All rats were Albumin/Globulin ratio (A/G ratio) was measured using administered balanced ration and water free from albumin and globulin values. medication. The food and drinking water were allowed ad.libitum throughout the experimental period. Rats were Serum Bilirubin: Serum total and direct bilirubin were maintained under standardized hygienic conditions measured [16]. The indirect bilirubin was measured (12:12 h light/dark cycles, the temperature was 24±2 °C through subtracting the obtained direct bilirubin from the and a minimum relative humidity of 45%) throughout total bilirubin. the experimental period. All rats were acclimatized for 2 weeks before starting the experiment. Comet Assay for Detection of Hepatic DNA Damage: The study was complied with the Animal Welfare Act. The alkaline comet assay was done using single cell gel The National Research Council Committee guidelines were electrophoresis according to [17]. Briefly, liver tissue (1 g) followed. was crushed and transferred to 1 mL ice-cold PBS, pH 7.4 and homogenized with a Potter-Elvehjem Experimental Design: Rats were divided into four groups; type-homogenizer (Ikemoto Scientific Technology, Tokyo, Group I, served as control. Group II, melatonin was IP Japan). The suspension was centrifuged at 500 RPM/ 5 administered daily at a dose of 10 mg/kg b.wt for 10 days. min; the supernatant was aspirated and repeat Group III, melatonin pretreated for 10 days then centrifugation for 3 times in PBS. The last suspension was subcutaneous (S/C) injected with a single dose of K2 Cr 27 O centrifuged at 3000 RPM/10 min to sediment hepatic cells. 15 mg/kg b.wt. Group IV, was S/C administered K2 Cr 27 O , An aliquot of the cell suspension was mixed with 0.5% 15 mg/kg b.wt. dissolved in distilled water. The samples low melting agarose then spread using a cover slide were collected 24 h post KCr2 27 O injection. on pre-coated slides with 1% normal-melting agarose, freeze for 2min then remove the cover slide. Then slides Blood and Liver Samples: Rats from all groups were were immersed in a lysis buffer over night. The slides were autopsied under light ether anesthesia 24 h post K2 Cr 27 O transferred to electrophoresis buffer in electrophoresis injection. The blood was drawn from the retro-orbital chamber. The current of electrophorsis was adjusted to venous sinus using capillary tubes. Blood was allowed to 300mA for 30 min. 324 Global Veterinaria, 16 (4): 223-329, 2016 Slides were stained with with 1% ethidium bromide at RESULTS 4 °C, then examined under a fluorescence microscope. About 50 to 100 random cells were selected and analyzed The Activity of the Hepatic Marker Enzymes (AST and per each sample and analyzed by Comet ScoreTM software ALT) of all Treated TM Rats was Evaluated: Group IV to calibrate the comet parameters. The software was used (K2 Cr 27 O treated rats) showed a significant (P<0.05) to evaluate the quantitative and qualitative DNA damage increase in the activities of the hepatic enzymes in the cells by measuring the tail length, tail DNA comparing with the control. Group II (melatonin treated) percentage and tail moment. showed a non significant change in the activities of these
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